Locking device



May 5, 1936.' E, F, TER Y 2,039,941

LOCKING DEVICE Filed Oct. 10, 1954 A \Q I 1N VEN TOR.

H125 ATTORNEY.

Patented May 5, 1936 UNITED STATES PATENT OFFICE LOCKING DEVICE Application October 10, 1934, Serial No. 747,723

4 Claims.

This invention relates to rock drills, and more particularly to a locking device adapted to hold the ratchet ring of the rotation mechanism of a rock drill fixedly in position.

One object of the invention is to enable the use of a ratchet ring having a thin imperforate wall and, consequently, to minimize the external diameter of the casing part containing the ratchet ring.

Another object is to effect a wide area of engagement between the ratchet ring and its securing means.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts in the several views,

Figure 1 is an end elevation, in section, of a rock drill equipped with a locking device constructed in accordance with the practice of the invention, and

Figures 2 and 3 are transverse views taken through Figure 1 on the lines 22 and 33 looking in the directions indicated by the arrows.

Referring more particularly to the drawing, designates a rock drill comprising a cylinder 2| and front and back heads 22 and 23, respectively, which constitute the casing parts of the rock drill. Within the cylinder is a reciprocatory hammer piston 24 having a fluted extension 25 at its front end to slidably engage a chuck 26 rotatable in the front head and interlockingly engaging a working implement 21 against which the hammer piston 24 strikes.

The movement of the hammer piston 24 is effected by pressure fluid which is conveyed to the ends of the cylinder by front and rear inlet passages 28 and 29 controlled by a suitable valve device, only the chest 30 of which is shown.

In order to effect a rotary movement of the working implement 21 between blows of the hammer piston 24 the rock drill is equipped with the usual rifle bar 3| which extends into the cylinder, to interlockingly engage the piston, and is journalled in-a plate 32 constituting a closure for the rear end of the cylinder. The plate 32, moreover, serves as a seat for a head 33 of the rifle bar and for one end of spring-pressed pawls 34 carried by the head 33.

Encircling the head 33 and extending, in the present instance, into the adjacent ends of the cylinder and the back head is a ratchet ring 35 of which the teeth 36 carried on its inner periphery form abutments for the pawls 34. The ratchet ring is of greater height than the head 33 and in the rear end thereof lies a flange 31 having teeth 38 on its periphery and of the same conformation as the teeth 36 wherewith they mesh.

The flange 31 is preferably an integral part of a plug 39 extendingg through the back head 23 to serve as a receptacle for cleansing fluid supply mechanism 40 including a tube 4| which extends through the percussive element of the rock drill and into the working implement 21. The plug 39 may be afiixed to the back head in any well known manner, preferably by press fitting, and the back head 23 is in turn held against rotary movement, with respect tothe cylinder 2|, by side rods 42 which also serve to secure the front head 22 to the cylinder 2 I.

In practice, the present invention has been found to be highly desirable as a means for holding the ratchet ring in fixed position in the casing of the rock drill. Owing to the toothed engagement between the flange 31 and the teeth of the ratchet ring a large effective area is provided between these elements for holding the ratchet ring immovable in the casing. A further highly desirable advantage of the present invention is that by thus employing portions of the ratchet teeth the ratchet ring may remain imperforate and its wall may be of thin section, and consequently of smaller outer diameter than in structures wherein the ratchet ring is keyed to the casing.

I claim:

1. In a locking device, the combination of a rock drill casing, a toothed ratchet ring therein, and means in the casing in constant engagement with the teeth of the ratchet ring for holding said ratchet ring in fixed position in the casing.

2. In a locking device, the combination of a rock drill casing, a rifle bar therein, pawls carried by the rifle bar, a ratchet ring having teeth to serve as abutments for the pawls, and means afiixed to the casing having teeth to mesh with the teeth of the ratchet ring for holding the ratchet ring in fixed position.

3. In a locking device, the combination of a rock drill casing, a rifle bar therein, pawls carried by the rifle bar, a ratchet ring having teeth to serve as abutments for the pawls, a bushing aflixed to the casing and having a flange, and teeth on the periphery of the flange engaging the first said teeth for holding the ratchet ring in fixed position.

4. In a locking device, the combination of a rock drill casing, a ratchet ring therein, and means fixedly secured to the casing and constantly engaging the ratchet teeth of the ratchet ring for holding said ring against rotation relative to the casing.

EDWARD F. TERRY. 

